NASA says Curiosity has found Mars could have supported primitive life (updated)

View full sizeThe image on the left is of rocks seen by the earlier Mars rover Opportunity. On the right are rocks seen by Curiosity. The particles on the rocks at left were formed by water, NASA says, but the area was believed too acidic for life. On the right, however, the fine-grain sediments are evidence of an ancient habitable environment. (NASA photos)

WASHINGTON -- NASA scientists said Tuesday, March 12, 2013, that the Curiosity rover found conditions suitable for ancient life on Mars in its very first drilling below the planet's surface. So far, the rover has found evidence of water and a "chemical energy source," in the words of NASA lead scientist John Grunsfeld. If the rover can find carbon compounds, Grunsfeld tweeted Tuesday, "then Mars has the ingredients for life."

The environment suitable for life appears to be "older than 3 billion years," Curiosity project scientist John Grotzinger said, which is roughly the same time as the first evidence of life on Earth. Grotzinger said the environment found by Curiosity "is so benign that if this water was around and you were on the planet, you would have been able to drink it."

"A fundamental question for this mission is whether Mars could have supported a habitable environment," said Michael Meyer, lead scientist for NASA's Mars Exploration Program. "From what we know now, the answer is yes."

When the first drill cuttings were revealed to be gray, rather than red,
scientists realized they had found something different. It turned out
to be "a mixture of oxidized, less-oxidized, and even non-oxidized
chemicals providing an energy gradient of the sort many microbes on
Earth exploit to live," NASA said.

Specifically, the rover found "sulfur, nitrogen, hydrogen, oxygen, phosphorus and carbon -- key chemical ingredients for life -- in powder Curiosity drilled out of a sedimentary rock near an ancient stream bed in Gale Crater on the Red Planet last month," said a NASA briefing website.

Scientists will drill a second time in the same area to confirm their findings after Curiosity emerges from a month-long shutdown in April caused by solar conditions. After that drilling in May, it will begin its journey to Mount Sharip, a mountain that is Gale Crater's central mound. Early analysis from space of the mound's exposed layers has already revealed clay and sulfate minerals, and NASA theorizes those layers will offer more information about the duration and diversity of the habitable conditions on Mars.

(This story was updated at 2:10 p.m. CDT to include more details and quotes)